Agitator for use in bleaching flour



Feb. 12, 1924; B. NEAL ET AL AGITATOR FOR USE IN BLEACHING FLOUR Filed Jan. 18, 1923 fl w/5515.

INVENTORS Burton Meal 8 H. Hebrand ATTORNEY Patented Feb. 12, 1924.

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Application filed January 1a, 1923. Serial as. 618,851.

To allwizom it may co7wem.'

Be it known that we, BURTON NEAL and Gnonun H. HEBEBRAND, citizens of the United States, residing in the city of St. Louis and Kinloch, county of St. Louis, respectively, and State of Missouri, have invented new and useful Improvements in Agitators for Use in Bleaching Flour, of

which the following is a specification.

This invention relates to the art of whitening or bleaching flour, and has for. its general object the provision of a gas-tight agitator which will permit the application of the bleaching gas to the flour without permitting the escape of the gas into the mill.

The agitators as generally used for this purpose are not gas-tight, with the result that much of the bleaching gas escapes into the mill, with the result that more gas has to be generated and conducted to the agitator. where it is brought in contact with the flour, than would be necessary if all of the gas led into the agitator were ab- Sorbed by the flour. In addition to the disadvantage of waste alluded to, certain gases are used in this process of bleaching, notably chlorine, which is extremely detrimental to inhale, and it is therefore very desirable that such gas should not be allowed to escape into the mill room to be inhaled by the operators.

Various attempts have been made to obviate the leakage of gas from the agitator, but, so far as we are aware, all the devices of the character heretofore proposed have been faulty in operation, particularlyin the fact of lack of uniformity or continuity in the sealing of the gas from escape.

Our invention, therefore, is characterized by a construction which permits the continuous feed of flour into the agitator and its continuous escape therefrom under conditions which operate to seal both the inlet to and the outlet from the agitator without, in any manner, interfering with the continuity of'the operation. The bleaching gas is supplied to the agitator in regulated quantities as usual, but, in the case of our invention, the quantity of gas supplied may be greatly reduced from the amount which it is commonly found necessary to supply, and, as none of the gas can escape from the agitator, the volumetric flow thereof may be so regulated that all of the gas sup lied to the agitator will be absorbed by the our,

and only an amount of-gasnecessary to effeet the proper lightening bf the color of the flour need be so supplied.

In addition to the general bhject of the invention above set forth, other objects of the invention relate to details of construction and to combinations and operations of parts, which will be more clearly understood from the detailed description to follow. 4

The invention is illustrated in the accompanying drawing, in which- Figure 1 1s a top plan view of an agitator constructed according to our invention;

Figure 2 is a vertical sectional View thereof on the line 22 of Figure 1; Figure 3 is a horizontal sectional view on the line 3.3 of Figure 2, illustrating the agitator wheel;

- Figure 4 is a horizontal sectional view on the line H of Figure 2, showing particu larly the duplex packer, or forced-feed, device; and

Figure 5 is a horizontal Sectional view on the line 55 of Figure '2, showing an impeller in the form of a rotary member 1 provided with curved blades for continuously forcing the flour from the sealing chamber.

Referring now to the drawing, the nu meral 1 indicates a cylindrical casing, which is of considerable height relative to its diameter, and is preferably constructed of metal lined with wood. lhe cylinder is hermetically closed at its upper end by a to 2 having a central elevatedv portion 3, w ich is provided centrally of its upper end with a bearing 4 for the upper end of a vertically disposed shaft 5, having secured thereon at its upper end a beveled gear 6. Mounted onthe top 2 are standards 7 providing in their upper ends bearings 8 for drical member 12 openat its lower end and forming the body of an upper sealing chamber. The bottom of the chamber 12 is normally closed by 'a cap 13, the flanged portion 14: of which is adapted to fit against the lower end of the cylindrical megnber, or

chamber, 12. The cap 13 is normally pressed upwardly to close the lower end of the chamber 12 by means of headed rods passing through the bottom of the cap 13 and extending upward through the. chamber and through apertures in the top 2 and being supported on the upper ends of coil springs 16, which encircle said rods and rest at their lower ends upon the top 2. To pre vent the rods 15 from twisting in the operation of forcing the flour through the sealing chamber, as hereinafter described, we

preferably provide clips 17 secured on the inner circumference of the chamber 12 and having apertures through which the rods 15 pass. The elevated portion 3 is open at one side to provide an entrance for flour into the sealing chamber 12, and about this openingis secured the lower end of a spout 18, through which flour is continuously fed into the sealing chamber 12.

The cap 13 is preferably formed of hard rubber to prevent corrosion, and the chamber 12 may be constructed of the same material, or of metal, and suitably covered to protect it from corrosion. Of course, any other suitable substance or arrangement may be employed in the construction of the sealing chamber to prevent corrosion.

In the practice of our invention, it is intended that the flour fed into the sealing chamber 12 shall be continuously discharged therefrom without premitting the entrance of gas into the sealing chamber. This gas is fed to the main agitating chamber 1 through a pipe 19 having a downwardly disposed end 20 on the interior of the agitator for supplying the bleaching gas thereto.

To provide for the discharge of the flour into the agitator without permitting the escape of gas into the chamber, the following feeding and discharge arrangement is employed:

Mounted on the shaft 5 within the sealing chamber 12 is a forced-feed device, comprising a hub 21, havin two inclined blades 22 mounted thereon. Klso mounted on the shaft 5 within the cap 13 is an impeller of the construction shown in Figure 5, which, however, is a view of the impeller located in the cap of the lower sealing chamber,

was later described, this impeller comprising a hub 23 having a series of curved blades 24 projecting therefrom. As the flour is fed into the sealing chamber 12 through the spout l8, and the shaft 5 being rotated, the flour will first fall upon the cap 13 and will rapidly fill up the lower portion of the sealing chamber 12. When sufiicient flour has passed into this chamber, the action of the inclined blades 22 will act in the nature of packers to force the flour downward, and, as this continues, the increased pressure upon the cap 13 will cause the edge of its flange 14 to be moved from the bottom edge of the sealing chamber to provide an open space. The impeller 13 being continuously rotated, acts to force the flour outward toward the periphery of the cap 13 and through the opening provided between said cap and the lower end of the cylinder, so that it is thereby continuously forced outward into the agitating chamber 1. The open position of the cap 13 is indicated by dotted lines in Figure 2.

It will readily be seen that the flour itself, being constantly fed into the chamber 12 and forced downward against the cap by the blades 22, acts automatically to seal the opening made between the cap and the lower end of the chamber, as there will always be a more or less compact mass of flour within the chamber 12 and above the opening at its lower end to prevent any passage of gas into the chamber. As a matter of fact, but little difficulty is encountered in sealing the agitator at the upper or inlet end, as both chlorine and peroxide of nitrogenthe two gases usually employed-are heavier than air and each tends to descend in the agitator.

To secure the intimate mixture of the fiour with the gas supplied to the agitator 1. we preferably mount on the shaft 5 toward the upper end of the agitator, a wheel 25 prpvided with numerous spokes 26 and vanes 27 for agitating, or distributing, the flour within the agitator 1 as it falls from the sealing chamber. In the lower end of the agitating chamber 1 is provided a spider 28, having a central bearing 29 for the lower end of shaft 5, and below this spider, the agitating chamber proper is shaped to provide a conical outlet 30, through which the treated flour may pass to the bins, or packers. The lower end of the agitating chamber is mounted on a cylindrical support 31.

In order to permit the discharge of the treated fiour from the lower end of the agitating chamber 1 without, at the same time,

ermitting the escape of gas from said chamr, we provide the following construction:

Secured toward the lower end of the agitating chamber 1 by soldering, riveting, or

otherwise, is a funnel-shaped spout 32 which 1 receives the flour falling through said chamber and delivers it into a cylindrical extension of said spout, providing a lower sealing chamber 33. The lower end of this chamber is open, as in the case of'the upper sealing chamber, and is designed to be closed by a cap 34, which is slidably mounted on the shaft 5, as is the cap 13. This cap also is designed to fit against the lower end of the sealing chamber 33 and is yieldingly supported in its closed position by means of headed rods 35, which-pass through and have their heads in engagement with the underside of lugs 36, secured on the flange of cap 34. These rods pass through lugs 37 secured near the lower end of the chamber 33 and at their on the outside thereof, upper ends engage the upper ends of coil springs 38, which, at their lowerends, rest upon the lugs 37. The chamber 33 is provided with a forced-feed device 39 similar to that in'the upper sealing chamber, and also with an impeller 40 similar to that in the upper sealing chamber.

It will be seen that the spout 32 seals the agitating chamber 1 against escape of flour or gas at its lower end except through the sealing chamber 33.

The operation in connection with the lower sealing chamber is exactly like that described with reference to the upper sealing chamber; that is to say, the cap 34 will be forced downward, "by the operation of the forced-feed device 39 on the flour, against resistance of springs '38 to make an opening at the bottom of the sealing chamber 33 and the flour will be thrown out through said opening by the impeller 40. For the reason that a body of flour will always be maintained in compact condition within the sealing chamber 33, no free gas can pass out of the sealing chamber with the flour, as, in the first place,

it will be mechanically stopped by the body of flour in the sealing chamber; and, in the second place, owing to the reduced quantity of gas which we are able to employ in the agitating chamber, all gas reaching the sealing chamber 33 would be absorbedbythe flour therein before it would have an opportunity of escaping with the flour, in the form of gas.

For the purpose of maintaining the wall of the spout 32 free of adhering flour, we preferably mount on the shaft 5, to turn with it, an arm 41 having a scraper 42 on its outer end, which is designed to be rotated by the shaft over the surface of said spout 32, and thus keep it clean.

The shaft 5 and other metallic parts within the agitating chamber 1 are preferably covered with rubber to prevent corrosion by contact with the gas, and the cap 34, chamber 33 and spout 32 will preferably be made of hard rubber, or of some other material, which will not be afiected by contact with the gas employed. I

The numeral 43 indicates the cover for a hand-hole which permits access to the --interior of the agitator in the plane of the discharge end of the lower sealing-chamber, so that the operator can secure samples of flour andlascertain, by examining the same, the degree of the bleaching action effected, and thus determine whether to supply more or less gas to the chamber.

From the above description, it will be seen that the sealing chamber in connection with the spout 32 provide within the casing 1 a chamber which is normally closed by the caps .13 and 34 against e'scape of gas, so

that when the agitator is not in operation, any gas remaining in the agitator will be prevented from escaping. It will also be seen that when the device is in operation, the

passed through the agitator, nevertheless it is possible to operate the device without using these impellers.

We wish it understood that the invention is not limited to the precise details of construction shown in the drawings and described herein,but that modifications of the invention could be made without departing from the broad scope of the invention as outlined in the claims.

We claim:

' 1. A device for use in subjecting flour to the action of a gas, comprising an extended casing providing a gas-tight chamber, means located, respectively, at opposite ends of said chamber for continuously compressing and feeding flour into. and continuously compressing and discharging it from the chamber, thereby maintaining the seal of the chamber by means of said compressed bodies of flour, and means for supplying a gas to said chamber.

2. A device for use in subjecting flour to the action of a gas, comprising an extended casing providing a gas-tight chamber, flour feeding means and flour discharging means located, respectively, at opposite ends of said chamber, yieldab-le means associated with the flour feeding and discharging means and operating to offer resistance to the entrance of the flour into and its discharge from said chamber, whereby compressed bodies of flour will be formed and act as seals to prevent the escape of gas from the inlet to or the discharge from the chamber, and means for admitting a gas to said chamber.

3. A device for use in subjecting flour to the action of a gas, comprising an extended casing providing a gas-tight chamber, receptacles open at either end supported at opposite ends of said chamber, one of said receptacles being open to the chamber. yieldable closures covering corresponding ends of each receptacle, means for admitting flour to the other receptacle, means in each receptacle for forcing flour therein against its closure to open it, and thereby provide a com- 1 pact body of flour beyond the opening to seal the same, and means for supplying a gas to said chamber.

4. A device for use in subjecting flour to the action of a gas, comprising a vertically disposed casing providing a chamber, receptacles open at either end supported at opposite ends of said chamber, the lower of said receptacles being open to the chamber and the chamber being hermetically sealed between said receptacles, a yieldable closure covering the lower end of each receptacle, means for admitting flour to the upper receptacle, means in each receptacle for forcing flour therein against its closure to open it, and thereby provide a compact body of flour above the opening to seal the same, and means for supplying a gas to said chamber.

5. A device for use in subjecting flour to the action of a gas, comprising a vertically disposed casing providing a chamber, receptacles open at either end supported at opposite ends of said chamber, the lower of said receptacl s being open to the chamber and the chamber being hermetically sealed between said receptacles, yieldable closures covering the lower ends of each receptacle, means for admitting flour to the upper receptacle, means in each receptacle for forcing flour therein against its closure to open the same, each discharging flour receptacle for through the opening made by the closure,

. a top providing an opening,

and means for supplying a gas to said chamher.

6. A device for use in subjecting flour to the action of a gas, comprising a "ertically disposed casing providing a chamber, receptacles open at either end supported at opposite ends of said chamber, yieldable closures covering the lower end of each receptacle, means for admitting flour to the upper receptacle, a shaft extending through said receptacles and from top to bottom of said casing, means for driving said shaft, a forced-feed device mounted on said shaft within each receptacle, an impeller mounted on the shaft at the lower end of each recep tacle, and means for supplying a gas to said chamber, the said chamber being closed except for the openings through said receptacles.

7. A device for use in subjecting flour to the action of a gas, comprising a vertically disposed casing providing a chamber having a receptacle secured to the under side of said top about said opening and open at either end, a cap for closing the lower end of said receptacle, spring-supported rods normally holding said cap in its closed position, means for admitting fiour through said opening to the remeans located at the lower end of memo? ceptacle, a conical member secured in said casing toward its lower end and open to said chamber and having a cylindrical downwardly extending portion forming a. receptacle, a cap for closing the lower end of said receptacle, spring-supported rods normally holding said cap in its closed position, a vertically disposed shaft extending through said receptacles, means for driving said shaft. a forced-feed device located on said shaft within each receptacle, an impeller mounted on said shaft at the lower end of each receptacle, an agitating member secured on said shaft below the upper receptacle, and means for admitting gas to said chamber.

8. A device for use in subjecting flour to the action of a gas, comprising a vertically disposed casing providing a chamber having a top providing an opening, a receptacle secured to the under side of said top about said opening and open at either end, a cap for closing the lower end of said receptacle, spring-supported rods normally holding said cap in its closed position, means for admitting flour through said opening to the receptacle, a conical member secured in said casing toward its lower end and open to said chamber and having a cylindrical downwardly extending portion forming a receptacle, a cap for closing the lower end of said receptacle, spring-supported rods normally holding said cap inits closed position, a vertically disposed shaft extending through said receptacles, means for driving said shaft, a forced-feed device located on said shaftwithin each receptacle, an impeller mounted on said shaft at the lower end of each receptacle, an agitating member secured on said shaft below the upper receptacle, a scraper mounted on said shaft and rotatable thereby over the surface of said conical member, iaJnd means for admit-ting gas to said chamer. a

9. The method which consists in continuously passing flour into and discharging it from a container while admitting a bleaching gas thereto, and maintaining a body of compressed flour at the inlet to and discharge from the container, respectively, to act as sea-ls to prevent the escape of gas from the chambe In testimony whereof, we have hereunto set our hands.

BURTON NEAL. GEORGE H. HEBEBRAND. 

